A WPS is a document that describes how welding
is to be carried out in production. They are recommended for all
welding operations and many application codes and standards make them mandatory

What information should they include?

Sufficient details to enable any competent person
to apply the information and produce a weld of acceptable quality.
The amount of detail and level of controls specified on a WPS is dependant
on the application and criticality of the joint to be welded.

For most applications the information required is
generally similar to that recorded on a Procedure Qualification Record
(PQR) or Welding Procedure Approval Record (WPAR), except that ranges are
usually permitted on thicknesses, diameters, welding current, materials,
joint types etc.

If a WPS is used in conjunction with approved welding
procedures then the ranges stated should be in accordance with the approval
ranges permitted by the welding procedure.

However careful consideration should be given to
the ranges specified to ensure they are achievable, as the ranges given
by welding procedure standards do not always represent good welding practice.
For example welding positions permitted by the welding procedure standard
may not be achievable or practical for certain welding processes or consumables.

EN ISO 15609-1 (formally EN 288 Part 2) European Standard For
Welding Procedure SpecificationsEN ISO 15609 Defines the contents of a Welding
Procedure Specification in the form of a list of information that should
be recorded. For some applications it may be necessary to supplement
or reduce the list. For example only in the case of a procedure requiring
heat input control would there be a necessity to quote travel speed or
run-out length for manual processes.

ASME IX American Boiler and Pressure
Vessel CodeQW 250 Lists the variables for each welding process,
all the variables stated should be addressed. The range permitted
by the WPS is dictated by the PQR or PQR’s used to qualify it.

Typical Items That Should Be Recorded On W.P.S:-

Common to all Processes
.

Procedure number

Process type

Consumable Size, Type and full Codification.

Consumable Baking Requirement if applicable

Parent material grade and spec.

Thickness range.

Plate or Pipe, Diameter range

Welding Position

Joint Fit Up, Preparation, Cleaning, Dimensions etc.

Backing Strip, Back Gouging information.

Pre-Heat (Min Temp and Method)

Interpass If Required (Maximum Temperature recorded )

Post Weld Heat Treatment. If Required (Time and Temp)

Welding Technique (weaving,max run width etc.)

Arc Energy Limits should be stated if impact tests are required
or if the material being welded is sensitive to heat input.

Specific To Welding Processes

MMA

TIG

MIGMAGFCAW

SUBARC

Welding current

yes

yes

yes

yes

Type of Welding current AC/DC Polarity

yes

yes

yes

yes

Arc voltage

If Auto

yes

yes

Pulse parameters (Pulse time and peak & backgound current)

If Used

If Used

Welding Speed If Mechanised

yes

yes

yes

Wire configuration

yes

Shielding gas (comp,flow rate)

yes

yes

Purge gas (comp & flow rate)

If Used

If Used

Tungsten electode Diameter and type.

yes

Nozzle diameter

yes

yes

Type of Flux Codification & Brand Name

yes

Nozzle Stand Off Distance (Distance from tip of nozzle to workpiece).

yes

SketchesA sketch of the joint configuration is required which
should include the basic dimensions of the weld preparation. Some
indication of the run sequence is also beneficial, particularly if the
correct sequence is essential to ensure the properties of the weld are
maintained.

Production SequenceWhilst this is good practice it is not a requirement of either
ASME 9 or EN288 Part 2; it could be issued as a separate QA procedure if preferred.